1. Field of the Invention
The subject invention relates to ammunition transport systems for loading and feeding ammunition. More particularly, the invention relates to apparatus for providing a simple lightweight ammunition transport system capable of uploading and downloading ammunition into and from a gun system, ensuring proper orientation of the rounds, protecting ammunition from handling hazards, and functioning under a wide range of environmental conditions.
2. Description of Related Art
The ammunition loading system impacts logistics and supportability from the LAP (load, assemble and pack) facility to the flight line. Ammunition represents virtually all of the gun system weight and volume that will be transported and handled worldwide during the system's life and, accordingly, places great demands on manpower. Even in peacetime, the requirement to demonstrate combat capability of each combat unit at least quarterly causes hundreds of thousands of rounds to be recycled through storage areas every year.
The cumbersome clothing used to protect personnel from chilling arctic weather or chemical and biological pollutants makes the operation of loading systems even more difficult. In many cases, the loading task occurs in cramped quarters with poor visibility and often in conditions that make even fair weather operation difficult.
A wide variety of technologies, loading concepts, and ammunition containers are in use with today's small and medium caliber aircraft gun systems. The level of integration of the LAP package in the overall system is an important discriminator between the various concepts. For most systems the utility of the LAP package ends at the storage area, while with others, specifically the A10 the aircraft is loaded directly from the LAP package at the flight line. Hypothetically, the ultimate integration would incorporate the LAP package directly into the aircraft, becoming an integral part of a modular aircraft feed system.
The current A10 system utilizes the ammunition container packaged at the LAP facility as an integral part of the flight line loader assembly. The 30-mm A10 ammunition is stored in plastic "link tube carriers" that are connected by a fabric rope. Thermal expansion problems at both low and high temperatures have detrimentally affected the system's performance by effecting the extraction of the round from the link tube carriers. This potential problem indicates the desirability of designing a system that is operationally insensitive to the LAP configuration. This can be accomplished by a loading system that is independent of the LAP package, or by a loading system that is carefully designed to remain unaffected by environmental extremes as well as long duration storage.
As indicated above, the majority of today's ammunition loading systems do not use the LAP package on the flight line. These systems can be segregated into two broad categories: linked loaders and linkless loaders.
Although linked ammunition loading systems are predominant today, they are being replaced by linkless technology. Briefly, the procedure required to load 20-mm ammunition with a linked loading system includes temporarily linking the ammunition at the storage facility (if prelinked ammunition is not available). Link belts are then placed in modules that are transported to the flight line, where they are fed through a flex chute to an interface unit that is attached to the aircraft access/transfer unit. The system is typically powered by a pneumatic drive. Rounds are delinked by the interface unit and handed off to the aircraft access/transfer unit. Simultaneously, links, spent brass, and bypassed rounds drop into an open chute and fall into an empty module on the trailer. The rough and uncontrolled handling during the downloading process contributes to the high rejection rate of reprocessed ammunition.
The universal loader (UALS) Part No. 212F156, developed and manufactured by General Electric, will upload/download various aircraft. With this system, based on rotary linkless technology, the loading procedure at the flight line is similar to the linked systems in that the loader interface unit is attached to the aircraft access/transfer unit and powered by an air wrench drive assembly. This system includes an integral pneumatic system.
The major benefit of this loading concept is the absence of links during the loading operation. A well designed mechanism can handle bulk ammunition more reliably than linked ammunition. In addition, downloaded material (again excluding links) is returned in an orderly and controlled fashion to the loader, which minimizes damage to reprocessed ammunition. The UALS concept also facilitates potential automation of the returned munitions inspection and repackaging procedure.
The shape of the 20-mm AGT cased telescoped ammunition versus conventional M-50 series ammunition impacts loading system considerations both beneficially and detrimentally. Beneficially the simplified exterior shape can be defined by a length, a diameter and corner radii. The constant diameter minimizes the number of rotor configurations required and eliminates additional guides to support the smaller bourrelet diameter. Conventional ammunition requires the definition of dozens of features (rotating band, ogive, meplat, bourrelet, extractor groove, case neck, etc.). Each of these features effects the design of the packaging, loading, and feeding systems.
However, the AGT cartridge structure imposes some handling constraints in that it utilizes higher strength material and is inherently stronger in half-inch zones at both ends of the cylindrical cartridge than the center. Therefore, round control should be accomplished by avoiding the center of the case.
The reliability of linear linkless concepts has been proven in the last ten years. Prior to acceptance of the technology, opponents argued that the chain used to transport rounds through the storage container represented the foremost drawback in the system. Many different sizes and styles of chain have been incorporated in linear linkless designs including: 8-mm, 0.25-inch pitch and 0.375-inch pitch.
Although the reliability issue is no longer an obstacle, cost has replaced it; at least in the case of loading systems that utilize the LAP package as part of the loader. It has occurred to the inventors that a significantly cost-reduced system for linkless loading could be produced if the chain ladder transport mechanism could be replaced with a wire rope ladder transport mechanism.
Steel wire rope is a common material utilized in aircraft control systems. The environmental specification (MIL-W-83420-D) defines a usable temperature range from -65.degree. F. to +248.degree. F., and high resistance to dirt, dust, and solvents. Having conceived of the idea of using wire rope in an ammunition loading system, the inventors have recognized a considerable number of obstacles to achieving a successful device. These obstacles include the necessity to successfully:
a. Join wire rope ends to form a continuous loop in the face of considerable loads PA1 b. Attach cross bars to provide round control PA1 c. Sustain high numbers of flex cycles traveling over pulleys PA1 d. Maintain acceptable crossbar pressure angles PA1 e. Install a continuous wire rope ladder in a storage container